This gene is a member of the protein-tyrosine kinase oncogene family. It encodes a membrane-associated tyrosine kinase that has been implicated in the control of cell growth. The protein associates with the p85 subunit of phosphatidylinositol 3-kinase and interacts with the fyn-binding protein.FYN is implicated in the control of cell growth.FYN is required in brain development and mature brain function with important roles in the regulation of axon growth, axon guidance, and neurite extension. FYN blocks axon outgrowth and attraction induced by NTN1 by phosphorylating its receptor DDC.